1. Technical Field
The present disclosure relates to the technical field of light emitting diode (LED) driving circuits, and more particularly, to an LED backlight driving circuit.
2. Description of Related Art
In the prior art LED backlight driving circuits, a boost circuit (i.e., a boost converter or step-up converter) is usually used to power an LED.
Referring to FIG. 1, the boost circuit comprises a first inductor L0, a second inductor L, a diode D, a first capacitor C0, a second capacitor C, a metal-oxide-semiconductor field-effect transistor (MOSFET) Q and a resistor R. Herein, the MOSFET is simply called MOS transistor. The first inductor L0, the second inductor L, the diode D and the first capacitor C0 are connected in series with each other in sequence and then connected in parallel with the second capacitor C. A branch formed by the MOS transistor Q connected in series with the resistor R has one end connected between the first inductor L0 and the second inductor L, and the other end connected between the first capacitor C0 and the second capacitor C. In the boost circuit, an input voltage is filtered by the second capacitor C to obtain a stabilized direct current (DC) voltage, and a voltage across the first capacitor C0 is boosted by the first inductor L0 and the second inductor L; and a square wave driving circuit is used to control the MOS transistor Q so that a voltage can be supplied to the LED by the first capacitor C0 when the MOS transistor Q is turned on.
However, when the load becomes greater as the number of LEDs increases, a plurality of boost circuits must be used instead of the single boost circuit to power the LEDs, which adds to the cost.